Stator core for dynamo-electric machine and manufacturing method therefor

ABSTRACT

A claw-pole type dynamo-electric machine, from which an improvement in productivity of stator winding can be expected, has such as a structure that the whole stator wiring is covered with a magnetic body, and thereby the inductance increases to pose the problem of decreasing a power factor. Disclosed is a stator core of a dynamo-electric machine in which a plurality of stator cores of respective phases are arranged independently in the direction of the rotating shaft of a rotor, the magnetic poles of the stator cores are arranged in the shape of a wave in the circumferential direction of the rotating shaft of a rotor, slots extending in the direction of the rotating shaft are formed between respective magnetic poles, and the stator winding can be arranged in a slot formed on the side of the inner end face of the magnetic pole arranged in the shape of a wave and in the axial direction of the rotating shaft.

TECHNICAL FIELD

The present invention relates to a stator core for a dynamo-electricmachine having a stator and a rotor, and a manufacturing methodtherefor.

BACKGROUND ART

The prior art dynamo-electric machine used for example in a motor or apower generator adopted a complex stator winding, which caused drawbackssuch as low productivity. Claw-pole type dynamo-electric machines asdisclosed in patent document 1 or patent document 2 are known as anexample of a dynamo-electric machine having improved productivity.

-   [Patent document 1] Japanese patent application laid-open    publication No. 2006-296188-   [Patent document 2] Japanese patent application laid-open    publication No. 2005-151785

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

In a claw-pole motor type dynamo-electric machine as disclosed in patentdocument 1 or patent document 2, there is a drawback in that the statorwinding has high inductance. For example, when the inductance of thestator winding becomes high in a motor or a power generator, the phasedifference between the current and the voltage is increased, by whichthe power factor, which is a principal characteristics of the motor orthe power generator, is deterorated.

The object of the present invention is to provide a stator core of adynamo-electric machine in which the stator productivity is high, andwhich can reduce the increase of inductance of the stator winding.

SUMMARY OF THE INVENTION

The present invention provides a stator core for a dynamo-electricmachine having a rotor supported in a rotatable manner, and a statorhaving at least two stator cores aligned in a rotating shaft directionof the rotor, each stator core comprising a plurality of magnetic polesof the stator core arranged in a circumferential direction of therotating shaft of the rotor, and stator core slots formed in an axialdirection of the rotating shaft between the respective magnetic poles ofthe plurality of magnetic poles, wherein the respective magnetic polesarranged in the circumferential direction have end faces in the axialdirection of the rotating shaft formed in a shape of a wave with respectto adjacent magnetic poles in the axial direction of the rotating shaft,so that a stator winding can be arranged in the slots formed on the sideof the wave-shaped inner end faces of the magnetic poles and in theaxial direction of the rotating shaft, and wherein the magnetic poles ofthe plurality of stator cores arranged in the circumferential directionof the rotating shaft are formed of steel sheets laminated in the axialdirection of the rotating shaft.

Further, the present invention provides a manufacturing method of astator core for a dynamo-electric machine comprising a step one forcutting out a material from a steel sheet, a step two for laminating thematerial, a step three for joining the material and a step four forforming the material in a shape of a wave, wherein steps one throughfour are combined to form a plurality of magnetic poles of a stator corein the circumferential direction of a rotating shaft of thedynamo-electric machine, to form slots in an axial direction of therotating shaft between the respective magnetic poles of the plurality ofmagnetic poles, and to form end faces in the axial direction of therotating shaft of the respective magnetic poles arranged in thecircumferential direction so that the adjacent magnetic poles arealternately displaced in a shape of a wave in the axial direction of therotating shaft.

Effect of the Present Invention

The present invention enables to either suppress the increase of theinductance or reduce the inductance of the stator winding.

Further according to preferred embodiments of the present invention,there are no claws extending in the axial direction disposed between thecircumferential stator winding and the rotor surface as seen in commonclaw-pole type stators, so that the stator cores can be manufacturedeasily in an advantageous manner.

According further to the preferred embodiments of the present invention,there are no claws extending in the rotating shaft direction between thecircumferential stator winding and the rotor surface and linked to thestator winding, so that the inductance of the stator winding can bereduced compared to common claw-pole type stators.

Further according to the preferred embodiments of the present invention,the area of the magnetic body surrounding the stator winding 122 issmaller compared to common claw-pole type stators, so that theinductance of the stator winding can be reduced significantly.

According further to the preferred embodiments of the present invention,the stator winding is arranged in the rotating shaft direction and therotor cores are divided into phase units and aligned in the rotatingshaft direction as in common slot teeth dynamo-electric machines, sothat the manufacturing of the stator winding is facilitated, and theproductivity thereof is effectively improved. According to the preferredembodiment of the present invention, the stator winding is arranged inthe rotating shaft direction between the magnetic poles arranged in thecircumferential direction, so that the surface of the magnetic poles ofthe stator opposed to the rotor can be increased compared to commonclaw-pole type magnetic poles, and the efficiency can be improved.

According further to the preferred embodiments of the present invention,the magnetic poles of the stator are formed by stacking stator cores inthe axial direction, so that iron loss caused by eddy current can be cutdown significantly.

Even further, since laminated steel sheets are used in the embodimentsof the present invention, the mechanical strength of the stator issignificantly increased compared to those using power magnetic cores.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing the basic structure of a statoraccording to a preferred embodiment of the present invention;

FIG. 2A is a perspective view showing the whole body of the basicstructure of the stator according to one example;

FIG. 2B is a partial cross-sectional view of the basic structure of thestator illustrated in FIG. 2A;

FIG. 2C is a partial cross-sectional view showing yet another view ofthe basic structure of the stator shown in FIG. 2A, which is a partialcross-sectional view perpendicular to a rotating shaft of the basicstructure of the stator illustrated in FIG. 2A;

FIG. 3 is a perspective view showing a stator core of the basicstructure of the stator illustrated in FIG. 1;

FIG. 4 is a perspective view showing a stator core of the basicstructure of a stator according to the other example of FIG. 2;

FIG. 5 shows yet another embodiment of the stator core illustrated inFIG. 3;

FIG. 6 is a stator winding used in the basic structure of the statorshown in FIGS. 1 and 2;

FIG. 7 is a perspective view of a stator according to a preferredembodiment of the present invention;

FIG. 8 is an expansion diagram of the stator illustrated in FIG. 7;

FIG. 9 shows a first example of a manufacturing method according to onepreferred embodiment of the present invention;

FIG. 10 shows a second example of a manufacturing method according toone preferred embodiment of the present invention;

FIG. 11 shows a third example of a manufacturing method according to onepreferred embodiment of the present invention;

FIG. 12A is a plan view of a material shape of the stator core, whereinthe material is an annularly connected member;

FIG. 12B shows a shape in which a plurality of magnetic pole sectionsare connected in a strip shape with a polarizability;

FIG. 12C shows a shape in which a plurality of magnetic pole sectionsare connected linearly in a strip shape;

FIG. 13 is a perspective view of a manufacturing step in which thematerial is layered spirally;

FIG. 14A is a perspective view of a step for forming a material in theshape of a wave, showing the state prior to forming the material in theshape of a wave;

FIG. 14B is a view showing the state after forming the material in theshape of a wave;

FIG. 15A shows a pair of stator core poles, illustrating the pair ofstator core poles shown in FIGS. 3 through 5;

FIG. 15B shows a pair of stator core poles with a flange;

FIG. 15C shows a pair of stator core poles according to yet anotherexample;

FIG. 16A shows another embodiment of the manufacturing method of astator corresponding to a single phase;

FIG. 16B shows yet another embodiment of the manufacturing method of astator corresponding to a single phase;

FIG. 17 is a perspective view showing another embodiment of the statorcorresponding to a single phase;

FIG. 18A is a partial cross-sectional view of a stator winding;

FIG. 18B is a partial cross-sectional view of a stator winding;

FIG. 18C is a partial cross-sectional view of a stator winding;

FIG. 18D is a partial cross-sectional view of a stator winding;

FIG. 19A is a perspective view prior to assembling, illustrating theapplication of the stator core to a dynamo-electric machine; and

FIG. 19B is a perspective view after assembling, illustrating theapplication of the stator core to a dynamo-electric machine.

DESCRIPTION OF REFERENCES

100 three-phase AC stator

102 stator

102U U-phase stator

102V V-phase stator

102W W-phase stator

104 stator core

104U U-phase stator core

104V V-phase stator core

104W W-phase stator core

106A teeth

106B teeth

108 flange

112 rear side section

114 slots

116 welding section

122 stator winding

122U U-phase stator winding

122V V-phase stator winding

122W W-phase stator winding

124 interpolar section

126 magnetic pole end section

128 magnetic pole end section

130 magnetic insulating panel

401 outer circumference

404 rotor

412 bearing

414 bearing

416 rear side housing

418 front side housing

436 shaft

452 through bolt

1001 material

1101A punch

1101B punch

1102A counter

1102B counter

1103 stopper

BEST MODE FOR CARRYING OUT THE INVENTION

Now, a preferred embodiment of the present invention will be describedwith reference to the drawings.

[Description of the Basic Structure of a Stator]

We will now describe the basic structure of a stator 102 according toone preferred embodiment of the present invention with reference toFIGS. 1 through 6. FIG. 1 is a perspective view showing the basicstructure of the stator 102 according to one preferred embodiment of thepresent invention.

FIGS. 2A through 2C illustrate another preferred embodiment of the basicstructure of the stator shown in FIG. 1, wherein flanges 108 aredisposed on the respective magnetic pole sections 106 in the basicstructure shown in the embodiment of FIG. 1. FIG. 2A is an overall viewof the basic structure of the stator 102 according to another example,FIG. 2B is a partial cross-sectional view of the basic structure of thestator 102 according to FIG. 2A, and FIG. 2C is yet another partialcross-sectional view showing another view of the basic structure of thestator 102 shown in FIG. 2A, which is a partial cross-sectional viewperpendicular to a rotating shaft of the basic structure of the stator102 shown in FIG. 2A.

FIG. 3 is a perspective view showing a stator core 104 according to thebasic structure of the stator 102 shown in FIG. 1, and FIG. 4 is aperspective view showing a stator core 104 according to the basicstructure of the stator 102 of the other example shown in FIG. 2.Further, FIG. 5 shows yet another embodiment of the stator core 104illustrated in FIG. 3. FIG. 6 shows a stator winding 122 used in thebasic structure of the stator 102 illustrated in FIGS. 1 and 2.

The basic structure of the stator 102 as shown in FIG. 1 or FIGS. 2Athrough 2C is composed of a stator core 104 and a stator winding 122. Onthe rotor-side of the basic structure of the stator 102, magnetic polesections 106 acting as the magnetic poles of the stator 102 are disposedat even intervals across the whole circumference of the stator, whereinthe magnetic pole sections are alternately denoted by reference numbers106A and 106B merely for the convenience of describing the operationthereof hereafter, and the magnetic pole sections 106A and 106B actuallyoperate in the same manner. A rotor mentioned earlier is disposedrotatably on the inner side of the magnetic pole sections 106A and 106B,but for sake of easier description, the rotor is not shown in FIGS. 1through 4.

In a dynamo-electric machine, the stator 102 can be disposed on eitherthe outer side of the rotor or the inner side of the rotor, and eitherstructure can be adopted in the present embodiment, but for sake ofeasier description, the present embodiment is described with the statordisposed on the outer side of the rotor. If the present invention isused as an AC power generator, a Rundle-type rotor is adopted as therotor. It is also possible to adopt a permanent magnet rotor having apermanent magnet disposed on the surface or in the interior thereof, aflux barrier rotor for generating a reluctance torque by restricting themagnetic flux of axis D or axis Q, or a squirrel-cage rotor, wherein theabove-mentioned rotor and the stator 102 can be combined to form adynamo-electric machine, and the dynamo-electric machine can operate asa motor or a generator in the respective applications.

The basic structure of the stator 102 illustrated in FIG. 1 and thebasic structure of the stator 102 illustrated in FIGS. 2A through 2C arevery similar, but according to the basic structure illustrated in FIGS.2A through 2C, flanges 108 are provided on the magnetic pole sections106 on the side of the rotor toward the directions of the adjacentmagnetic poles, by which the area of the side surface of the rotor inthe basic structure of the stator 102 is increased and the outputcharacteristics thereof is improved. Further, the stator core 104illustrated in FIG. 5 shows yet another embodiment of the stator core104 illustrated in FIGS. 3 and 4, wherein rear side sections 112connecting the adjacent magnetic pole sections 106 are curved so as toimprove the productivity.

As shown in FIGS. 2A and 2B, magnetic pole sections 106 are disposed atequal intervals on the circumferential surface perpendicular to therotating shaft, and since the magnetic pole sections 106 are altenratelydisplaced in the direction of the rotating shaft, recesses are formed atpositions corresponding to every other magnetic pole section 106 at theend in the rotating shaft direction in the basic structure of the stator102. A stator winding 122 is disposed in the recesses, so that theprojection of the stator winding 122 from the stator core 104 at the endof the rotating shaft can be reduced or eliminated.

FIG. 2C shows a cross-sectional view in which the magnetic pole sections106A and magnetic pole sections 106B illustrated in FIG. 2B arepartially cut away at a plane perpendicular to the rotating shaft. Asshown in FIG. 2C, slots 114 extending in the rotating shaft directionare formed between the respective magnetic pole sections 106A andmagnetic pole sections 106B, and in the slots 114 are stored the statorwinding 122. The difference between the present stator and the prior artstator is that a single-phase winding is inserted to the slots 114, andthat the structure of the stator winding 122 is simple. Thus, thepresent stator has superior productivity and improved reliability. Asshown in FIG. 2C, the respective magnetic pole sections 106 areconnected via the rear side section 112. Further, flanges 108 are formedon the rotor side of the respective magnetic pole sections 106, and therotor side of the respective slots 114 are narrowed by the flanges 108.According to this structure, the area of the surface opposing to therotor is increased, and the characteristics of the dynamo-electricmachine are improved.

The stator core 104 shown in FIGS. 3 through 5 is the stator core 104 ofthe basic structure of the stator 102 as shown in FIGS. 1 and 2, whereina plurality of magnetic pole sections 106 are disposed on the rotor sideat even intervals across the whole circumference thereof. In the presentembodiment, 20 magnetic pole sections 106 are disposed. These magneticpole sections 106 are respectively connected with adjacent magnetic polesections 106 at the rear side section 112, and spaces 114 or slots 114extending in the direction of the rotating shaft are formed between theadjacent magnetic pole sections 106 for inserting the stator winding.

In the stator core 104 illustrated in FIGS. 1 through 5, magnetic polesections 106 are alternately displaced in the rotating shaft direction,wherein the magnetic pole sections 106A are displaced toward the otherside with respect to the magnetic pole section 106B. According to thisstructure, spaces are formed on one side of the magnetic pole sections106 to enable the stator winding 122 to be arranged therein, so that thestator windings 122 can be prevented from projecting to one side, andthe basic structure of the stator 102 can be downsized. Copper loss canbe minimized. Similarly, since the magnetic pole sections 106B aredisplaced toward one side with respect to the magnetic pole sections106A, a space is formed on the other side of the magnetic pole sections106. By arranging the stator winding 122 in this space, the statorwinding 122 can be prevented from projecting to the other side, and thebasic structure of the stator 102 can be downsized as mentioned earlier.Further, copper loss can be minimized.

However, the alternately displaced arrangement of the magnetic polesections 106 as described above is not indispensible, and the presentstator without the displaced arrangement is still extremely superior tothe stator of the prior art dynamo-electric machine from the viewpointof productivity, since the basic structure of the stator 102 of thedynamo-electric machine enables the winding operation of the statorwinding 122 to be performed extremely easily. Further, the presentembodiment effectively reduces the inductance of the statorsignificantly compared to the common claw-pole type stator as disclosedin patent document 1 or patent document 2 in which a large number ofclaws are disposed on the side of the rotor.

The stator core 104 illustrated in FIGS. 3 through 5 have weld sections116 in which the outer circumferential surface of the rear side section112 on the side opposite from the magnetic pole section 106 are fixedvia welding. The stator core 104 is formed by winding continuousmagnetic steel sheets of a thin plate shape in the circumferentialdirection, as described in detail later, so as to improve theproductivity and cut down material waste. Since the welding sections 116are formed on the outer circumferential surface of the rear side section112 corresponding to the respective magnetic pole sections 106, themagnetic pole sections 106 can be easily displaced in the rotating shaftdirection by winding the continuous thin-plate magnetic steel sheet inthe circumferential direction and forming the stator and thereafter therear side section 112 via pressing or the like at the weld sections 116.

FIG. 6 illustrates the stator winding 122 used in the basic structure ofthe stator 102, and in the present embodiment, the stator winding 122 iswound in a wave shape. Concentrated windings other than wave winding canbe used, but the present embodiment is illustrated taking as an examplea wave-shaped stator winding 122. The wave-shaped stator winding 122shown in FIG. 6 has a continuous shape in which interpolar sections 124of the stator winding is connected to magnetic pole end sections 126 onone side of the stator winding 122 and magnetic pole end sections 128 onthe other side of the stator winding. The interpolar sections 124 of thestator winding 122 are mutually connected to the magnetic pole endsections 126 on one side of the stator winding 122 or to the magneticpole end sections 128 on the other side of the stator winding 122, andthe magnetic pole end sections 126 on one side of the stator winding 122are respectively inserted to slots 114 having a shape extending in therotating shaft direction of the stator core 104 as illustrated in FIGS.2 through 5.

Recesses are mutually formed at axial direction ends of the stator core104 corresponding to the magnetic pole sections 106, and the magneticpole end sections 126 on one side of the stator winding 122 is insertedto the recesses formed on one end of the stator core 104, and themagnetic pole end sections 128 on the other side of the stator winding122 are inserted to the recesses formed on the other end of the statorcore 104. As mentioned earlier, it is not always necessary to formrecesses on both ends of the rotating shaft of the stator core 104, andin that case, the magnetic pole ends 126 on one side of the statorwinding 122 and the magnetic pole ends 128 on the other side of thestator winding 122 are projected toward the direction of the rotatingshaft from both ends of the stator core 104.

When the winding illustrated in FIG. 6 is attached to the stator core104 as shown in FIGS. 3 through 5, the winding will be disposedalternately within the grooves 114 formed in the axial direction of thestator core 104, according to which all the slots are covered by thewinding in a similar winding form as a wave winding structure of aslot-teeth type motor. Therefore, the present embodiment has superiorelectric characteristics with respect to a claw-pole type stator havingclaws disposed between the stator 102 and the rotor.

[Description of a Stator for a Three-Phase AC Dynamo-Electric Machine]

The basic structure of the stator 102 as described earlier operates as asingle-phase stator with respect to the whole stator. Hereafter, athree-phase AC stator 100 will be described with reference to FIGS. 7and 8. FIG. 7 is a perspective view of a stator 100 of a three-phasedynamo-electric machine formed by assembling basic structures of stators102 as shown in FIG. 1 or FIG. 2. FIG. 8 is an expansion diagram of thethree-phase AC stator 100 illustrated in FIG. 7.

The three-phase AC stator 100 illustrated in FIG. 7 utilizes the basicstructure of three stators 102, respectively, as a U-phase stator 102U,a V-phase stator 102V and a W-phase stator 102W. The U-phase stator102U, the V-phase stator 102V and the W-phase stator 102W are alignedrespectively in the rotating shaft direction, wherein the rotor is usedin common, and the basic structures of the stators 102 of respectivephases are arranged so that they have mutual phases.

[Description of Phases]

When a stator 100 of a multi-phase dynamo-electric machine is formed byusing the basic structure of the stator 102 as described earlier, thestators of respective phases are arranged independently in the axialdirection. As for the relative positional relationship of stators ofrespective phases, if the machine is a two-phase dynamo-electricmachine, the basic structures 102 of the stators are arranged with a90-degree phase difference of electric angles. In other words, thestators are disposed so that the mechanical angles of one pair of poleson the rotor side are displaced by ¼.

In the case of a stator 100 for a three-phase dynamo-electric machine,the stators are arranged with a 120-degree phase difference in electricangles. In other words, the stators are disposed so that the mechanicalangles per pair of poles on the rotor side are displaced by ⅓. FIG. 7illustrates an example of a stator 100 of a three-phase dynamo electricmachine. FIG. 7 illustrates a stator of a three-phase dynamo-electricmachine having 20 poles. Since there are 20 poles, the number of polepairs is 10. Therefore, the mechanical angle of displacement of polesbetween one phase and another phase is ⅓ of 36 degrees which is themechanical angle of 10 pole pairs, in other words, 12 degrees.

The above description illustrates a structure in which the rotor isshared with respect to the basic structures of respective stators 102constituting the three-phase AC stator 100, and wherein the rotor has nophase. By using the rotor as a common structure, the structure of thewhole body of the dynamo-electric machine can be simplified, which issignificantly effective from the viewpoint of downsizing and improvingproductivity of the stator. Especially when the above-mentioneddynamo-electric machine is used as an AC power generator, the basicstructure of the respective stators 102 constituting the three-phase ACstator 100 can share the common disclosed winding, according to which ahigh power output can be obtained.

However, it is also possible not to provide any phase to the mountingposition of phases on the stator side, but instead, to divide the rotorside corresponding to the respective phases and arrange the poles on therotor side corresponding to the respective stators to have phases forconstituting the multi-phase dynamo-electric machine as described above:This relationship of phases is the same as the relationship describedwith reference to the stator.

Two-phase AC and three-phase AC as typical examples of the stator 100 ofa multi-phase dynamo-electric machine have been described up to now, butthe present embodiment enables the stator to correspond to AC havinggreater phases. For example, in order to form a stator 100 of asix-phase AC generator, six basic structures of the stator 102 can bearranged in the axial direction, and a phase of 60 degrees in electricangle should be provided thereto. By dividing the six-phase AC generatorper three phases and parallely-connecting the same after rectification,the maximum current per phase can be reduced and the current capacity ofa rectifier circuit or the like can be minimized.

[Description of Structure of a Three-Phase Stator]

FIG. 7 shows a stator 100 for a three-phase AC dynamo-electric machineas a typical example of a stator 100 for a multi-phase dynamo-electricmachine. The actual structure of a three-phase AC stator 100 will bedescribed with reference to FIG. 8. The basic structures of the stator102 described in FIGS. 1 and 2 are arranged as three stator blocks,which are a U-phase stator 102U, a V-phase stator 102V and a W-phasestator 102W, aligned in the axial direction. In the present arrangement,magnetic insulation members having a magnetic shielding effect forreducing flux leakage between phases are disposed between the phases.The magnetic insulation members are not indispensible, and can bearranged if necessary, but the reduction of flux leakage leads toimprovement of efficiency and enhancement of characteristics.

The insulation material should preferably be composed of a nonmagneticmaterial such as a polymeric material, or ceramic and other materialhaving no conductivity. Furthermore, improvement of radiationperformance can be expected by adopting a material having good thermalconductivity. Further, although not shown in the drawings, it ispossible to realize highly accurate positioning of the stator blocks byproviding slots, holes, projections, socket joints or other fittingfunctions on the magnetic insulation member 3 for determining theposition of the stator core. This positioning is important since thecircumferential positions or the coaxialness of the stators influencethe torque ripple of the dynamo-electric machine.

It is also possible to form a magnetic shield using metallic materials.Actual preferable examples of metallic materials include aluminumalloys, nonmagnetic stainless steel alloys and copper alloys. If wedisregard the problem of cost, light-weight titanium can be used.Examples of resin materials include LCP (liquid crystal polymer), PPS(polyphenylene sylfide resin), PBT (polybutylene terephthalate resin),PET (polyethylene-based resin), glass fiber-reinforced nylon and PC(polycarbonate resin). Further, carbon fiber-reinforced resin orepoxy-based and unsaturated polyester-based thermosetting resin can beused. The material should be determined based for example onrestrictions of thermal and mechanical strength required for the motoror generator to which the stator is applied.

As for the manufacturing method of these materials, aluminum and copperalloys can be formed via die casting, and stainless steel and otheralloys can be formed via machining, cold forging and warm forging.Resin-based material can be formed via processes such as injectionmolding. When metal-based materials are used, the shape should bedetermined with care regarding the developmental pathway of eddycurrent.

[Manufacturing Method of Stator Core 104]

The manufacturing method of a stator core will now be described withreference to FIGS. 9 through 11. The manufacturing method of the statorcore 104 is composed of a step for cutting out a material 1001 from asteel sheet, a step of laminating the materials 1001, a step of joiningthe materials 1001, and a step of forming the materials 1001 in theshape of a wave. The stator core 104 can be formed via steps as shown inFIG. 9 in the named order; cutting out the steel sheet, laminating thecut out materials 1001, joining the cut and laminated materials 1001,and forming the cut, laminated and joined materials 100 in the shape ofa wave; or via steps as shown in FIG. 10 in the named order; cutting outthe steel sheet, laminating the cut out materials 1001, forming thelaminated materials 1001 in the shape of a wave, and joining thematerials 1001 formed in the shape of a wave; or via steps as shown inFIG. 11 in the named order; cutting out the steel sheet, forming thematerials 1001 in the shape of a wave, laminating the materials 1001formed in the shape of a wave, and joining the laminated materials 1001.

In the step of cutting material out of a steel sheet illustrated inFIGS. 9 through 11, the material sheet is cut into shapes havingexpanded the magnetic pole sections 106 and the rear side sections 112.Methods for cutting the material include, for example, shearing such aspunching using a press machine, wire cutting, laser cutting, plasmacutting, water jet cutting and machining, but it is preferable to adoptpunching using a press machine considering productivity.

FIGS. 12A through 12C illustrate shapes of the cut out material 1001.The shape is either continuously connected in an annular shape as shownin FIG. 12A, or one or more magnetic poles of the magnetic pole section106 and the rear side section 112 are connected in a strip shape asshown in FIGS. 12B and 12C. According to the material 1001 connectedannularly, the accuracy of the inner and outer diameters of the material1001 is good, but the yield is not good since the material at the centersection is not used. On the other hand, according to the material shapein which one magnetic pole or a plurality of magnetic poles of themagnetic pole sections 106 and the rear side section 112 are connectedin a strip shape, the yield is good, but the accuracy of the diametersmust be ensured in the following lamination process.

In the step of laminating the materials 1001 illustrated in FIGS. 9through 11, the materials are laminated so that the magnetic polesections 106 are aligned in the axial direction of the rotor. Themagnetic pole sections 106 can be aligned in the axial direction of therotor, for example, by using recessed shapes formed on the rear sidesection 112 of the materials 1001 as a guide when laminating thematerials. Further, the material shape at this time can be annular, orcan have one or more magnetic poles of the magnetic pole sectionsconnected in a strip shape. According to the material shape wheremultiple magnetic poles of the magnetic pole sections 106 and the rearside section 112 are connected in a strip shape, the material islaminated spirally as shown in FIG. 13. At this time, the linear shapedmaterial 1001 is formed into a circular arc shape by performing in-planebending in the circumferential direction. For example, the material 1001is subjected to in-plane bending in the circumferential direction byrolling the rear side section 112 of the material 1001.

In the step of joining the materials illustrated in FIGS. 9 through 11,joining is performed after aligning the magnetic pole sections 106 andlaminating the same. Joining is performed for example via clinching inwhich a projected section and a recessed section formed via halfblanking are joined together, or via laser welding, TIG welding, bondingand so on. According to the “clinching” process in which the projectedsection and the recessed section formed via half blanking are joinedtogether, projected sections and recessed sections are formed via halfblanking on the material 1001 when cutting out the same, and then thematerial is pressed via a press machine or the like in the rotatingshaft direction after lamination to join the same. In the case of laserwelding or TIG welding, it is preferable to perform joining at the rearside section 112 which has little influence on the magnetic property.Further, when joining is performed using material having a magneticinsulation property, the magnetic property is improved, but if themember is used in a dynamo-electric machine, the member must be usedwithin a temperature range in which the adhesive will not fall off.

In the step for forming the material into a wave shape as shown in FIGS.9 through 11, magnetic pole sections 106A and 106B are alternatelyformed into a wave shape. The wave shape is formed by pushing in theaxial end face of the magnetic pole section 106A toward the direction ofthe rotating shaft relatively with respect to the axial end face of themagnetic pole section 106B. In the step for forming the material into awave shape, the magnetic pole sections 106A and 106B are moved in theradial direction of the rotating shaft, according to which the material1001 can be prevented from having reduced plate thickness or frombreaking due to the extension of the material 1001 in thecircumferential direction, and therefore, the formability is improved.Further, when the magnetic pole sections 106A an 106B are moved in theradial direction of the rotating shaft, the inner diameter accuracy ofthe stator core 104 can be improved by pressing the end face of themagnetic pole sections 106A and 106B in the radial direction of therotating shaft onto a tool. In the step of forming the material 1001into a wave shape, the material can be a single sheet or in a laminatedstate.

FIG. 14 shows an example of a step for forming a material into a waveshape, wherein FIG. 14A shows the state prior to forming the materialinto a wave shape, and FIG. 14B shows a state after forming the sameinto a wave shape. For sake of better understanding, the front side areaof the tool in the drawing at the upper side of the material 1001 is notshown, but actually, a tool is disposed in this area as in otherportions in the circumferential direction. Furthermore, in the step forforming the material 1001 in a wave shape, the material can be a singlesheet or in a laminated state, but in FIGS. 14A through 14C, thematerial 1001 is in a laminated state.

As shown in FIG. 14A, punches 1101 are arranged in the circumferentialdirection of the rotating shaft on the end faces of the magnetic polesections 106A and 106B to be pressed in toward the axial direction, andcounters 1102 are arranged so as to sandwich the material 1001 betweenthe punches 1101. The counters 1102 apply power in the thicknessdirection of the sheet composing the material 1001 in an oppositedirection from which the punches 1101 press the magnetic pole sectionsin the direction of the rotating shaft, to thereby restrain deformationof the material 1001 to the exterior of the plane. In the actual formingprocess, when the magnetic pole sections 106A are pressed in toward therotor axis direction, the magnetic pole sections 106B must be restrictedfrom moving in the rotor axis direction, or when the magnetic polesections 106B are pressed in toward the rotor axis direction, themagnetic pole sections 106A must be restricted from moving in the rotoraxis direction, but in the present description, since the magnetic polesections 106A and 106B are to be relatively deformed in the rotor axisdirection, the magnetic pole sections 106A are formed via a punch 1101Afor pushing the same toward the rotor axis direction, and the magneticpole sections 106B are formed via a punch 1101B for pushing the sametoward the rotor axis direction.

Further, parts corresponding to the punches 1101A and 1101B are referredto as counters 1102A and 1102B. The punches 1101A and 1101B are arrangedalternately around the circumferential direction of the rotor so thatthe direction in which the punches 1101A press the magnetic polesections 106A toward the rotor axis direction and the direction in whichthe punches 1101B press the magnetic pole sections 106B toward the rotoraxis direction are relatively opposite. Furthermore, counters 1102A and1102B are also arranged alternately around the circumferential directionof the rotor to correspond to punches 1101A and 1101B. In this state,the punches 1101A and 1101B are relatively pushed toward the rotor axisdirection so as to form a wave shape as shown in FIG. 12B. According tothis method, the bending radius of the rear side sections 114 connectingthe magnetic pole sections 106A and 106B are continuously increasedtoward the outer side in the radial direction of the rotor axis.

In the step of pushing the punches 1101 in the rotor axis direction, theformability can be improved by moving the magnetic pole sections 106 inthe rotor axis direction. By reducing the frictional force among thematerial 1001, the punches 1101 and the counters 1102, and/or byenabling the punches and the counters 1102 to be moved freely in theradial direction of the rotor, and/or by moving the punches 1101 and thecounters 110 forcibly via a cam mechanism in the radial direction of therotor, drawbacks caused by the expansion of the material 1001 in thecircumferential direction such as the reduction of sheet thickness andfracture can be suppressed, and the formability can be improved.Further, the inner diameter accuracy of the stator 104 can be improvedby butting the end face of the magnetic pole sections 106 in the radialdirection of the rotor against a stopper 1103 at a final stage when themagnetic pole sections 106 are deformed in the radial direction of therotor.

The counter 1102 is used to ensure the flatness of the magnetic polesections 106. Mold constructions such as die cushions, gas dampers orsprings are used to apply opposing force with respect to the punch 1101.A forming method using a counter 1102 has been described, but since themagnetic pole sections 106 can be curved to realize the sameperformance, the counter 1102 can be omitted if it is not necessary toensure the flatness of the magnetic pole sections 106. In that case, themagnetic pole sections 106A and 106B should simply be pressed usingpunches 1101A and 1101B, so that the forming process can be facilitatedusing a mold having a shape of a transferred waveform.

During the process for forming a waveform, when the magnetic polesections 106 are moved toward the radial direction of the rotor, theshape of the material 1001 projected in the rotor axis direction will bevaried before and after forming, so that the material 1001 prior toforming must have a shape having expanded the shape of the stator core104 after forming. Since the shape of the magnetic pole sections 106will not vary so much after the material is formed into a wave shape,the shape thereof can be the same as the shape of the stator core 104,but the length of the rear side section 114 must be set longer than thelength of the stator core 104 projected in the rotor axis direction.Further, the length of the rear side section 114 must be increased asthe amount of movement of the magnetic pole sections 106 in the radialdirection of the rotor increases.

Now, the actual manufacturing method of the stator core 104 will bedescribed. First, a material 1001 having multiple magnetic polescontinuously connected in a strip shape is cut out from a steel sheethoop material via a punching process. Next, the rear side section 112 ofthe material 1001 having multiple magnetic poles connected in a stripshape is bent in-plane via rolling, and the material is laminatedspirally as shown in FIG. 13. After laminating a desired number oflayers, the rear side section 112 of the material 1001 is welded vialaser welding. Next, the laser-welded material 1001 is formed into theshape of a wave via a press, according to which a stator core 104 asshown in FIG. 5 is manufactured.

An annually-connected or spiral stator core 104 has been described, butnow, a stator core 104 having been divided in the circumferentialdirection per a few magnetic poles will be described. From the viewpointof electric characteristics, it is not necessary that the stator core104 has an integral shape. FIGS. 15A through 15C show an example of acore shape composed of a pair of magnetic poles (two magnetic poles)constituting a magnetic circuit of the stator. FIG. 15A shows one pairof magnetic poles of the stator core 104 illustrated in FIGS. 3 through5.

According to the structure of the dynamo-electric machine used as amotor or a power generator, the flow of flux from the rotorcorresponding to one pair of magnetic poles covers the fluxcorresponding to one pair of magnetic poles on the rotor side, so thatthe flow of flux between adjacent magnetic pole pairs is not required.Therefore, characteristics equal to the stator core having an integratedshape can be satisfied by a core divided circumferentially into multipleparts. Therefore, by assembling core parts composed of teeth 106A and106B as illustrated in FIG. 15A to constitute a stator core 104, astator core having a structure as described earlier to be used in motorsand power generators can be formed. Further, the same reference numbersdenote portions having the same functions and effects as in the formerdescription.

FIG. 15B has a shape in which flanges are formed to the leading ends ofteeth 106A and/or teeth 106B of FIG. 15A. The flanges function tocollect the flow of flux from the rotor effectively, and to prevent thewound stator winding 122 from protruding to the inner direction. FIG.15C illustrates a core having a shape alternated in the axialdirections, wherein the positional relationship of the magnetic polesare not superposed in the rotating shaft direction. The presentembodiment devised the shape of the core so as to ensure a wide spacefor arranging the stator winding 122 and to simplify the shape of thestator winding 122 so as to improve the productivity and workability.The stator core 104 illustrated in FIGS. 3 through 5 or FIG. 17 have alaminated structure of magnetic thin sheets, but the structure thereofis not restricted to the laminated structure, and the stator core canalso be manufactured by compacting a power magnetic core or the like,for example. However, the laminated steel sheet structure is moreadvantageous from the viewpoint of strength, reliability and magneticcharacteristics. Though detailed descriptions of FIGS. 15B and 15C areomitted, the components denoted by the same reference numbers functionin the same manner and exert the same effects.

FIGS. 16A and 16B illustrate concepts for manufacturing a stator core104 corresponding to one phase worth of stator core using the coreillustrated in FIG. 15B. Interpolar sections 124 of the stator winding122 as shown in FIG. 6 are respectively inserted to slots 114 extendingin the rotating shaft direction between teeth 106A and teeth 106B.Thereafter, the respective magnetic pole pairs of FIG. 16A are fixed viawelding or the like to form a stator core 104A having an integral shapein the circumferential direction.

According to the structure illustrated in FIG. 16A or in FIGS. 1 through5, slots 114 are disposed along the rotating shaft, and interpolarsections 124 of the stator winding 122 are inserted to the slots 114. Onthe other hand, according to the example shown in FIG. 16B, the teeth106A and teeth 106B are completely displaced in the rotating shaftdirection. According to this structure, the stator winding 122 can beinserted to the slots 114 without providing much flexure in the rotatingshaft direction. Therefore, the stator winding 122 has superiorproductivity. Further, the stator winding 122 can be inserted to theslots 144 easily, according to which the stator winding has superiorworkability. However, the stator winding has drawbacks in that thecross-sectional area of the magnetic circuit facing the rotor is reducedand the output tends to be deteriorated. However, if it is not necessaryfor the output to be high, the stator winding is effective since theproduction cost is inexpensive.

The basic structure of the finally completed stator 102 is the same asthat illustrated in FIG. 1 or FIGS. 2A through 2C, wherein the statorwinding 122 is wound so as to extend back and forth between one end andthe other end along the rotating shaft as shown in FIGS. 2B and 2C. Thestator core 104 of the above drawing is partially overlapped at thecenter in the rotating shaft direction of the stator core 104 havingteeth 106A and 106B displaced in the rotating shaft direction, which issubstantially the same as the winding arrangement of a slot teeth-typedynamo-electric machine as shown in the cross section of FIG. 2C. Thus,the plane opposing to the rotor has an efficiently composed magneticcircuit, according to which superior electric characteristics can beobtained. On the other hand, the stator winding 122 is significantlysimplified compared to the slot teeth-type dynamo-electric machine,according to which superior productivity can be obtained, and since theshape of the stator winding 122 is simple, the stator winding hassuperior safety and reliability.

FIG. 17 shows yet another embodiment of the stator winding 122. In thestructure illustrated in FIGS. 1 and 2, the stator winding 122 is bentin a substantially orthogonal angle at a portion connecting thecircumferential area with the rotating shaft direction area. In otherwords, the stator winding 122 has a portion substantially parallel withthe rotating shaft. However, when an actual magnet wire with a coatingis bent orthogonally, the resin coating for insulation may be damaged,so that it is necessary to pay special attention during operation. It ispreferable to bend the wire with a certain curve R (radius). At thispoint, if shapes illustrated in FIG. 1 or FIGS. 2A through 2C are to beformed, it is preferable that special care is given in the operation forforming the stator winding 122.

According to the form illustrated in FIG. 17, slots 114 between teeth106A and 106B are widened in the circumferential direction. Theclearance between the magnetic poles of the core is widened so that theportion of the stator winding 122 extended in the rotating shaftdirection can be arranged obliquely. This structure is advantageoussince the curve R (radius) can be moderated, according to which theworkability can be improved. However, the structures shown in FIG. 1 orFIGS. 2A through 2C have a higher ratio of area occupied by the statorwinding 122 (ratio of cross-sectional area of the conductor with respectto the slot), according to which high output can be obtained easily. Itis preferable from the viewpoint of improvement of efficiency so as notto reduce the ratio of area occupied by the stator winding 122 in thestructure illustrated in FIG. 17.

FIGS. 18A through 18D show the cross-sectional view of a stator winding122 capable of increasing the area occupation ratio thereof. Normally,as shown in FIG. 18A, a magnet wire having a round cross section is usedas the winding, but it is possible to increase the area occupation ratioby using a rectangular magnet wire aligned as shown in FIGS. 18B or 18C.Further, if the stator winding 122 is manufactured in advance as shownin FIG. 6, which is integrated with the stator core 104 thereafter, itis preferable to additionally provide a step for forming thecross-sectional shape of the stator winding 122 into a preferable shape.In the process of forming the cross-sectional shape of the statorwinding 122, the area occupation ratio of the winding can be improved byforming the wire having a substantially round cross-sectional shape intoa shape as illustrated in FIG. 18D.

[Application of the Stator to a Dynamo-Electric Machine Such as a Motor]

FIG. 19B is a perspective view of a dynamo-electric machine having thethree-phase AC stator 100 illustrated in FIG. 7 applied to thedynamo-electric machine, and FIG. 19A is an expansion diagram of thedynamo-electric machine shown in FIG. 19B. A bearing 414 and a bearing412 are respectively fixed to a front-side housing 418 and a rear-sidehousing 416, and a shaft 436 is supported in a rotatable manner via thebearings 414 and 412. A rotor 404 is fixed to the shaft 436. Thethree-phase AC stator 100 shown in FIG. 7 is disposed on the outer sideof the rotor 404 with a clearance therebetween. By engaging thefront-side housing 418 and the rear-side housing 416 via through bolts452, the three-phase AC stator 100 can be fixed and supported betweenthe front-side housing 418 and the rear-side housing 416. Further, anouter ring 401 formed of aluminum material or the like is disposed onthe outer circumference of the three-phase AC stator 100, by which thedynamo-electric machine is airtightly sealed.

The above-described three-phase AC stator 100 operates as a powergenerator or as a motor by being combined with various rotors, and canbe applied to various uses. In any application, the three-phase ACstator 100 has superior productivity since the design of the stator 100,especially the design of the stator winding 122, is simple. According tothe above-described embodiment, the coil end of the stator winding 122in the axial direction can either be minimized or eliminated, accordingto which the stator can be downsized and copper loss can be minimized.

1. A stator core for a dynamo-electric machine having a rotor supportedin a rotatable manner, and a stator having at least two stator coresaligned in a rotating shaft direction of the rotor, the stator corecomprising: a plurality of magnetic poles of the stator core arranged ina circumferential direction of the rotating shaft of the rotor, andstator core slots formed in an axial direction of the rotating shaftbetween the respective magnetic poles of the plurality of magneticpoles; wherein the respective magnetic poles arranged in thecircumferential direction have end faces in the axial direction of therotating shaft formed in a shape of a wave with respect to adjacentmagnetic poles in the axial direction of the rotating shaft, so that astator winding can be arranged in the slots formed on the side of theinner end faces of the magnetic poles arranged in the shape of a waveand in the axial direction of the rotating shaft, and wherein themagnetic poles of the plurality of stator cores arranged in thecircumferential direction of the rotating shaft are formed of steelsheets laminated in the axial direction of the rotating shaft.
 2. Thestator core for a dynamo-electric machine according to claim 1, whereina bend radius of a rear side section of the stator connecting theadjacent magnetic poles is gradually increased in a continuous mannerfrom the rotating shaft of the rotor toward the outer side in the radialdirection of the rotor.
 3. A manufacturing method of a stator core for adynamo-electric machine comprising: a step one for cutting out amaterial from a steel sheet, a step two for laminating the material, astep three for joining the material, and a step four for forming thematerial in a shape of a wave, wherein steps one through four arecombined to form a plurality of magnetic poles of a stator core in thecircumferential direction of a rotating shaft of the dynamo-electricmachine, to form slots in an axial direction of the rotating shaftbetween the respective magnetic poles of the plurality of magneticpoles, and to form end faces in the axial direction of the rotatingshaft of the respective magnetic poles arranged in the circumferentialdirection so that the adjacent magnetic poles are alternately displacedin a shape of a wave in the axial direction of the rotating shaft. 4.The manufacturing method of a stator core for a dynamo-electric machineaccording to claim 3, wherein the material being cut out in step one islaminated in step two, the material being laminated in step two isjoined in step three, and the material being joined in step three isformed into the shape of a wave in step four.
 5. The manufacturingmethod of a stator core for a dynamo-electric machine according to claim3, wherein the material being cut out in step one is laminated in steptwo, the material being laminated in step two is formed in the shape ofa wave in step four, and the material being formed in the shape of awave in step four is joined in step three.
 6. The manufacturing methodof a stator core for a dynamo-electric machine according to claim 3,wherein the material being cut out in step one is formed in the shape ofa wave in step four, the material being formed in the shape of a wave instep four is laminated in step two, and the material being laminated instep two is joined in step three.
 7. The manufacturing method of astator core for a dynamo-electric machine according to claim 3, whereinin step four, an end face of the magnetic pole in the rotor axisdirection is relatively pressed toward a rotating shaft direction of therotor with respect to an end face of an adjacent magnetic pole in therotor axis direction.
 8. The manufacturing method of a stator core for adynamo-electric machine according to claim 3, wherein in step four, themagnetic pole is moved toward a center of a radial direction of therotating shaft of the rotor.
 9. The manufacturing method of a statorcore for a dynamo-electric machine according to claim 3, wherein in stepfour, a center-side face of the magnetic pole in the radial direction ofthe rotating shaft of the rotor is butted against a tool.
 10. Themanufacturing method of a stator core for a dynamo-electric machineaccording to claim 3, wherein in step four, at least two methodsselected from the following methods are performed in a single step,which are a method for pressing an end face of the magnetic pole in therotor axis direction relatively toward a rotating shaft direction of therotor with respect to an end face of an adjacent magnetic pole in therotor axis direction, a method for moving the magnetic pole toward acenter of a radial direction of the rotating shaft of the rotor, and amethod for butting a center-side face of the magnetic pole in the radialdirection of the rotating shaft of the rotor against a tool.
 11. Themanufacturing method of a stator core for a dynamo-electric machineaccording to claim 3, wherein in step one, the material is cut eitherinto an annularly connected shape, or into a strip shape in which one ora plurality of magnetic poles of the stator are connected.
 12. Themanufacturing method of a stator core for a dynamo-electric machineaccording to claim 3, wherein in step two, sheet materials being cutinto an annularly connected shape are laminated, or sheet materials inwhich one or a plurality of magnetic poles of the stator connected in astrip shape are laminated, or sheet material connected in a strip shapeis spirally laminated.
 13. The manufacturing method of a stator core fora dynamo-electric machine according to claim 3, wherein in step three,the sheet members are joined via engaging and clinching an projectedsection and a recessed section formed thereto by half blanking, or vialaser welding, TIG welding, or adhesive bonding.